Large companies which manufacture and sell products are typically composed of different departments. Each department may take on different responsibilities with respect to the products and therefore has a different way of managing product information.
For example, suppose that a company which produces and sells computers has a marketing department which presents information concerning the computers to potential customers. Further suppose that marketing department organizes the information by product line and, for each product family within a product line, the information is further organized by specific models. Suppose further that, in addition to the marketing department, the company has a support department which presents information concerning components of the computers. Further suppose that the support department organizes the information by component type and, for each component type, a set of product versions which support the component. In this case, the marketing and support departments each maintain their respective product information within separate hierarchies.
Further, in a conventional presentation of information, because each department separately manages the product information, they can have their own way of referring to the same product information.